Hi, I wrote a simple userscript to enrich the commit and pull request pages of GH. I find it useful to analyze big commits.
Tested on Firefox 17 / GreaseMonkey 1.5. It's basically a vanilla JS so should work as a bookmarklet also but I prefer this to fire automatically.
Looking forward to your comments. You can suggests enhancements / bugs on GH: https://github.com/jakub-g/greasemonkey-userscripts
Enjoy, Jakub